Process of making fiber for paper, &amp;c.



VIGGO DREW$EI\T, 0F BROOKLYN, NEW YORK.

PROCESS OF MAKING FIBER, FOR PAPER, 8w.

Itl'o Drawing. Application filed March 12, 1915, Serial No. 13,863.

Specification of Letters Patent.

Patented June i2, 191?.

Renewed February 27, 1917. Serial To all whom it may concern."

Beit known that I, Vrooo DREWSEN, a citizen of the United States, and resident of the borough of Brooklyn, county of Kings, city and State of New York, have made certain new and useful Improvements Relating to Processes ofMaking Fiber for Paper, 810., of which the following is a specification.

This invention relates especially to processes for converting cornstalks, bagasse or other generally similar fibrous material into fiber which is suitable for use for paper or other purposes by treating the raw fibrous material under pressure in a suitable monosulfite solution, such as sodium or potassium monosulfite until the connective tissue is sufiiciently converted or removed to efi'ect the separation of the fiber as hereinafter described.

The raw fibrous material, such as crushed cornstalks or bagasse, for instance, may be boiled in a suitable digester for four to eight hours or so under a pressure of forty to one hundred and twenty pounds per square inch more or less in an aqueous solution of suitable monosulfite, such as sodium monosulfite (Na SO the solution preferably being amply strong enough to effect the desired disintegration of the material, sodium monosulfite to-the extent of twentyfive per cent. of the dry weight of the raw fibrous material giving good results with ordinary grades of dried cornstalks and minimizing the danger that the cooked material will be objectionably discolored. When for instance the charge of cornst-alks has been boiled under about seventy pounds pressure in such a sodium monosulfite solution for five or six hours or so, the connective tissue is largely or wholly dissolved or removed and the liquor which is still alkaline in reaction to litmus is usually much lighter in color than corresponding soda waste liquor. By acidifying this yellowish waste liquor with acetic acid, etc., a tannin material may be secured of especial value or light colored leather. The monosulfite disintegrating solution seems to have a reducin action on the raw fibrous material as in icated by the fact that considerable quantities of sodium sulfate (Na SOQ are found in the waste liquor and can be crystallized on concentrating and cooling the liquor. The fibrous material which may be recovered to the extent of about forty to fortyfive per cent. or so of the dry weight of the colnstalks of a grayish white color and of great strength and of suificiently uniform consistency and color so that it can be used with little or no pre liminary treatment for paper making, indeed the fiber can be used without bleaching for some grades of newspaper. The cooked fiber after the ordinary washing processes is completely disintegrated and reduced to a substantially homogeneous fibrous material which has a soft feel or texture and is substantially free from the objectionable slimy or brittle or parchment like character of some cooked cornstalk material. The knots or joints of the cornstalks are so completely disintegrated by the chemical treatment as to practically disappear after cooking and washing or heating, and the pith cells are so transformed as to be soft and substantially indistiuguishable to the naked eye from the other material. The cooked fiber can be further treated in any desired way and may be readily bleached with ordinary chlorinated bleaches so as to secure a uniformly white material available for the higher grades of paper. Potassium monosulfite may be used instead of sodium monosulfite, or the disintegrating solution may comprise various mixtures thereof or more or less magnesium monosulfite which if largely relied on should be present in ample quantities to go into solution from time to time dur ng the process and effect the desired chemical action.

This invention has been described in connection with a number of illustrative materials, proportions, conditions, arrangements and orders of steps, to the details of which disclosure the invention is not of 3 course to be limited, since what is claimed as new and what is desired to be secured by Letters Patent is set forth in the appended claims:

11. The process of making .paper fiber from cornstalks which consists in boiling the raw fibrous material for five to SIX hours under a pressure of about sixty to seventy pounds per square inch in the absence of substantial proportions of free caustic or strong acid in an aqueous solution of suilicient sodium monosul fite to represent about 25% of the dry Weight of the raw fibrous material and remain alkaline to litmus throughout the disintegrating proc-' 'monosulfite to vremain alkaline to litmus v throughout the disintegrating process, until the connective tissue is dissolved or removed and a soft strong fibrous material produced. 3. The process of making paper fiber from cornstalks, bagasse or similar fibrous material which conslsts in boiling the raw fibrous material for five to six hours under a pressure of 40 to .120 pounds per square inch in the absence of substantial proportions of free caustic in an aqueous solution of sufiicient sodium monosulfite to representv about 25% of the dry weightof the raw fibrous material and remain alkaline to litmus througho ut the disintegrating process, until the connective tissue is dissolved, loosened or removed and produce soft strong fibrous material including pith material which may be directly used for paper making.

4. The process of making paper fiber fromcornstalks, bagasse or similar fibrous material which consists in boiling the raw fibrous material for five to six hours under a pressure of 40 to 120 pounds per square inch in the absence of large proportions of free caustic in an aqueous solution of sulficient sodium monosulfite to remain alkaline to litmus throughout the disintegrating process, until, the connective tlSSllGwjS dissolved or loosened or removed and produce soft strong fibrous materialincludinfg pith material which may be directly used for 7 paper making.

5. The process of making paper fiber from corns'talks, bagasse or similar fibrous material which consists in boiling the raw fibrous material under pressure in the absence of large proportions of free caustic in an aqueous solution of sufficient sodium monosulfite to remain alkaline to litmus throughout the-disintegrating process, until the connect'ive tissue is dissolved, loosened or removed and produce soft strong fibrous material including pith material.

6. The process of making paper fiber from cornstalks, bagasse or similar fibrousmate- 7. The process of making paper fiber from corns'talks or bagasse which consists inboiling the same under pressure 1n a disintegrating liquor consisting substantially of a monosulfite solution remaining slightly alkaline to litmus, until the ligneous connective tissue is substantially dissolved or removed and a soft stro g fiber produced which can be beaten direct y into newspaper without preliminary bleaching.

8. The process of making paper fiber from cornstalks or bagasse which consists in boiling the same under pressure in a disintegra'ting'liquor consisting substantially of a solution of monosulfite of a base, remaining slightly alkaline to litmus until the ligneous connective tissue is dissolved, loosened or removed to produce a soft strong grayish white fiber material including the pi'th cells. l 1

VTGGO' DREWSEN.

Witnesses:

HARRY L. DUNCAN, JESSIE B. KAY. 

